Characterization of the seafloor in Australia's coastal zone using acoustic techniques

Abstract

Australia's coastal shelf contains a diversity of marine habitats that require regular assessment in a cost-effective way. As part of the Coastal Water Habitat Mapping (CWHM) project of the Cooperative Research Centre for Coastal Zone, Estuary and Waterway Management (Coastal CRC), several shallow water regions along the western, southern and eastern Australian coasts have been surveyed using multi and single beam echo sounders. Acoustic observations were ground-truthed with stereo photography, video recordings and grab and core samplings. A 450-kHz Reson SeaBat 8125 multibeam echo sounder was employed to obtain high-resolution bathymetry and acoustic backscatter maps of the seafloor. A new approach to deriving backscatter imagery of the seafloor has been developed for high-frequency multibeam systems. Robustness of different backscatter characteristics with respect to recognition of different habitats and seafloor vegetation was examined. The results of acoustic recognition and localization of marine vegetation on the seafloor are in agreement with video observations.